I've attached a PDF with the breakdown of the part cost for a group buy of the SMD parts.

Looks like it would be about half the cost if 19 people were committed to the GB versus everyone buying their own parts.

I've only included SMD parts since they're easy to slip into a padded envelope along with the PCB. It also helps to control my costs. I'm already on the line several hundred for the PCB, and this adds another $400 to that.

There are a number of other parts that would benefit from a GB scenario, but I'll have to leave that to others if they'd like to give it a go. Things like the heatsinks, the input/output caps for the PSU, and especially the Caddock resistors could really benefit from a larger single purchase as they drop from $3.94 each down to $2.64 at 100 pcs. They might be even cheaper directly from Caddock.